Add RHEL 8 Support

[pugnacity]

Describe the bug
Role can't be applied to RHEL8 nodes

Expected behavior
RHEL 8 is supported
Actual behavior

TASK [dev-sec.ssh-hardening : install selinux dependencies when selinux is installed on RHEL or Oracle Linux] ********************************
Wednesday 15 January 2020  16:06:14 +0100 (0:00:00.097)       0:00:13.195 *****
failed: [pdl0400-aux0002.ad.nublar.de] (item=policycoreutils-python) => {
    "ansible_loop_var": "item",
    "changed": false,
    "failures": [
        "No package policycoreutils-python available."
    ],
    "item": "policycoreutils-python",
    "rc": 1,
    "results": []
}

MSG:

Failed to install some of the specified packages

OS / Environment

• RedHat 8.1 Ootpa
• Selinux enabled

Ansible Version

ansible 2.9.1
  config file = /home/adm00001/repos/ansible/ansible.cfg
  configured module search path = ['/home/adm00001/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /home/adm00001/dev/ansible_29/lib/python3.6/site-packages/ansible
  executable location = /home/adm00001/dev/ansible_29/bin/ansible
  python version = 3.6.8 (default, Oct 11 2019, 15:04:54) [GCC 8.3.1 20190507 (Red Hat 8.3.1-4)]

Role Version

7.0.0

Additional context
The package policycoreutils-python must be replaced with python3-policycoreutils in RHEL8

[pgporada]

What you need to do is install this role from the master branch rather than whatever old version that ansible-galaxy has cached.

$ cat requirements.yml 
---
- name: dev-sec.ssh-hardening
  src: https://github.com/dev-sec/ansible-ssh-hardening

ansible-galaxy install -r requirements.yml --force

RHEL/CentOS 8 support has been added in fdfa4d7. Maybe a new version should be published on Galaxy, to avoid issues from users ?

[rndmh3ro]

Yes, good idea. I'll try to find some time.

[DonEstefan]

Seems like Support for EL8 was added in #242 (changelog), but ansible-ssh-hardening/meta/main.yml was not updated accordingly. @rndmh3ro would you mind fixing that glitch in the next release?

[rndmh3ro]

Fixed: #298